multiple ip's one domain?

Hi all -

I am looking for information on how to implement server redundancy by way of multiple static IPs on distinct subnets (two different broadband connections with distinct static IP's) pointing at the same domain. I would like to continue providing service despite loss of one of the two connections.

I am curious if there is a way to do this with DNS; that is, to have a single domain pointed to by two distinct public IP addresses.

Presently, I have the following:

1. 2 nics on each platform.
2. 2 static public ip's on seperate subnets from different providers (i.e. 50.51.52.53 and 200.201.202.203)
3. 2 linksys routers on each connection.
4. multiple computers running Windows Server, Linux, and FreeBSD.

I have read a little about using a linux box as a router to reroute requests from a given IP to another IP. However, I woould prefer a simpler solution using strictly DNS (although I suspect that might not be possible), or at least one that uses the linksys routers (which have routing capabilities) instead of dedicating another computer.

Any insights? I hope this makes some sense!

Thanks in advance ...

Jeff